I am in a house that was built in 1921. It has knob and tube and is still running electricity that way. We've had an experienced electrician come and inspect all the wires and breaker box and retrofit all the plugs to be grounded. We asked him if cellulose could be blown in over the knob and tube and he said that'd be fine because the wires are still in good shape.

I called an insulation company with experience in knob and tube and they said it's fine, as well. Especially because cellulose is non-flammeable.

I still have reservations, though. Despite both the electrician and insulation company saying it's safe, I'm worried.

I'm in the same situation, but have been told exactly the opposite. It could just be that my wires are in worse condition than yours, but I was under the impression that K&T wires were undersized vs current wiring, therefore run hotter, and need the air space around them for cooling. I don't want to derail your plans, just repeating what I was told about my house.